The World Anti-Doping Agency has warned the British Olympic Association that it is now isolated in global sport in arguing that athletes found guilty of doping offences should face an additional ban barring them from the Olympic Games for life.

After Wada ruled that the BOA was no longer compliant with its code on Sunday the Wada director-general, David Howman, confirmed it would go to the court of arbitration for sport if the BOA appealed, as it has indicated it will do.

Howman said its decision was straightforward once the Cas had decided that an International Olympic Committee rule forbidding athletes from appearing in the Games that followed a ban should be dropped in the wake of a challenge from the United States Olympic Committee and the 400m gold medallist LaShawn Merritt.

"The board considered the report, which included the Cas decision in the IOC and USOC case and the implications for the BOA. The reasoning in the IOC decision was that article 45 of the IOC charter was deemed to be an extra sanction, and extra sanctions are not allowed under the code," Howman said. "Wada is responsible for anti-doping rules and all of our signatories have agreed they will conform with those rules. By going beyond them, a signatory is not conforming. It's really as simple as that. The decision the board took was that the BOA rule was an extra sanction."

If the BOA loses its appeal at the Cas, expected to be heard within three months, then the British athletes Dwain Chambers, and Carl Myerscough, and cyclist David Millar would be eligible for 2012.

The BOA has suggested that other countries, including New Zealand and Canada, are in the same boat because they too have extra bans that could be considered "additional sanctions". But Howman said those countries had only introduced their rules to reflect the IOC's charter and were in the process of amending them. "The IOC dropped the rule [and] the NOCs that have that rule have agreed it will be null and void," he said.

Howman said Wada's decision to find the BOA non-compliant was nothing to do with the wide‑ranging attack on Wada's methods by the BOA chairman, Lord Moynihan, last week, which he labelled "misguided".

"The decision the board took on Sunday is solely associated with the Cas decision. What we were disappointed with was Lord Moynihan's speech in which he not only talked about that decision but a lot of other things in terms of anti-doping. He was a little bit misguided and he wasn't really adhering to the factual situation. It does become disappointing when a person of his eminence takes that track."

The IOC has the ability to ban countries if they are not compliant with the Wada code but it has confirmed there is no chance of that happening and underlined its confidence in UK Anti-Doping's testing procedures.

"It is important to make it clear that the anti-doping agency in the UK – the UKAD [UK Anti Doping] – is fully compliant. The BOA has only been deemed non-compliant on a technicality rather than any unwillingness of the BOA to fight doping," an IOC spokeswoman saidon Monday.

"We are confident that the BOA and UKAD will do their utmost to ensure clean British athletes will compete in London and this ruling will have absolutely no effect on British athletes competing in London."

UKAD said it agreed with the BOA that the best place to resolve the issue was the Cas. "For all UK athletes, we hope that a definitive ruling can be reached at the earliest opportunity," it said in a statement.

Howman, who also confirmed that Wada's budget had been frozen at $27.9m (£17.8m) for the coming year due to the wider economic chill, said Moynihan was "just wrong" to say that the global anti-doping body was "toothless". But he did concede that there was more to be done to improve testing programmes to catch "sophisticated dopers".

"Wada does not undertake the testing, it is undertaken by national anti-doping agencies. We monitor the testing," said Howman. "We have indicated we are not that happy with testing programmes in that they are not detecting the sophisticated dopers. We think we need to do more from that perspective as we go forward."